Organic fouling of reverse osmosis (RO) membranes and its relation to foulant--foulant intermolecular adhesion forces has been investigated. Alginate and Suwannee River natural organic matter were used as model organic foulants. Atomic force microscopy was utilized to determine the adhesion force between bulk organic foulants and foulants deposited on the membrane surface under various solution chemistries. The measured adhesion force was related to the RO fouling rate determined from fouling experiments under solution chemistries similar to those used in the AFM measurements. A remarkable correlation was obtained between the measured adhesion force and the fouling rate under the solution chemistries investigated. Fouling was more severe at solution chemistries that resulted in larger adhesion forces, namely, lower pH, higher ionic strength, presence of calcium ions (but not magnesium ions), and higher mass ratio of alginate to Suwannee River natural organic matter. The significant adhesion force measured with alginate in the presence of calcium ions indicated the formation of a crossed-linked alginate gel layer during fouling through intermolecular bridging among alginate molecules.

Relating organic fouling of reverse osmosis membranes to intermolecular adhesion forces

Poly[2-(dimethylamino)ethyl methacrylate-co-ethylene glycol dimethacrylate] (PDE) thin films were synthesized via initiated chemical vapor deposition (iCVD) and reacted with 1,3-propane sultone to obtain the zwitterionic structure. The cross-linker ethylene glycol dimethacrylate (EGDMA) was utilized to make the copolymer insoluble in water. The composition of the copolymer was tuned by varying the flow rates of precursors and calculated from Fourier transform infrared spectroscopy (FTIR) spectra. The zwitterionic coatings were covalently grafted on to reverse osmosis (RO) membranes, and surface characterizations were carried out. Scanning electron microscope (SEM) and atomic force microscope (AFM) revealed that the iCVD zwitterionic coatings were conformal and smooth over the RO membrane, and the coating thickness can be measured by using ellipsometry. Salt rejection was not impaired by the coating. Permeation tests were carried out under different feed pressures, film thicknesses, and film compositions, ...

Surface-Tethered Zwitterionic Ultrathin Antifouling Coatings on Reverse Osmosis Membranes by Initiated Chemical Vapor Deposition

Canada’s oil sands industry uses large volumes of freshwater to extract bitumen from surface-mined ore. With oil production expected to increase 3-fold over the next decade, process water treatment...

Process water treatment in Canada’s oil sands industry: II. A review of emerging technologies

http://membrane-recovery.com/show_file.php?file_id=23

Salt cleaning of organic-fouled reverse osmosis membranes

https://scholarworks.umass.edu/cgi/viewcontent.cgi?article=1489&context=open_access_dissertations

Mauno Into

Papers

Reuse of industrial wastewater following treatment with reverse osmosis